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Energy question of the week: Is complete self-sufficiency possible with decentralised power stations?

Nearly 80 percent of the electricity used in Europe comes from central power plants to the consumer via the electrical grid. As the popularity of renewable power sources has risen, consumer awareness of the importance of decentralised power production has also grown. The trend for decentralised and intelligent electricity production enjoys further support from projects for networked thermal power stations. Does this technology have the potential to provide an all-inclusive power supply?

At first glance, it might seem contradictory to create more decentralised power plants while also extending the electricity grid. But put both strategies together and you have a sustainable electrical energy supply for the future, because decentralised power stations alone cannot hope to meet the EU's annual power demand – around 3000 terawatt hours – on an indefinite basis. Large-scale plants – whether coal power or a vast wind farm in the North Sea – will also form the basis for a more secure supply in the future.

In practice, cities and energy-intensive industries will continue to rely on power generated in large-scale plants. On the other hand, there’s a good chance that decentralised production in rural areas or serving intelligently-designed residential zones will play an increasingly important role. In Germany, this trend is supported by the '100 percent renewable energy zones' initiative. Increasingly, communities are planning to bring together various types of power station – from wind turbines, to solar systems, to biogas generators – to create 'virtual power plants'. With these cooperations, fluctuating power supplies can be regulated to make way for a reliable decentralised supply of electricity and heat. "Decentralised power plants could provide 20-30 percent of Germany's electricity production in the next ten years," says Manfred Aigner, Director of DLR's Institute for Combustion Engineering in Stuttgart.

The microgas turbine at the test stand of DLR's Institute for Combustion Technology in Stuttgart, image: DLR.

Flexible and low-maintenance: the microgas turbine

As a result, DLR researcher Axel Ernst Widenhorn and his team are currently developing a small-scale power station which can deliver electricity as well as heat for households, hospitals or entire tower blocks. At the heart of the project is a microgas turbine which, fuelled by natural gases, is expected to reach as high an efficiency rating as possible. In this small gas turbine, a dense, hot jet of gas sets a generator turbine into motion with outputs ranging from very low to a maximum of 500 kW. Compared to conventional gas engines, these mini power stations have a number of advantages: They can run on a variety of fuels, emit very few pollutants and require low maintenance due to their simple construction.

In the near future, these gas turbines are expected to be able to use biogas efficiently. With this aim, DLR has teamed up with industry in a recently-launched project to initiate a drive towards having these mini power plants ready for production within a few years. Following on from this, researchers are developing a hybrid power plant by coupling microgas turbines with a fuel cell to drive up efficiency levels even further. As well as being able to provide self-made electricity and heat, each and every mini power station would offer individuals the chance to put power back into the grid. Under intelligent control, a home owner could become a small-scale power provider in the future. Communities with 'virtual power stations' and even individual households will be able to join the future electrical energy market, dominated by large-scale providers today, boosting competition in turn.

The DLR Energy question of the week in 'The future of energy' Year of Science

The Federal Ministry of Education and Research (BMBF) has given the Year of Science 2010 the motto 'The future of energy'. For this reason the science journalist Jan Oliver Löfken will this year answer a question on the subject of energy in his blog each week. Do you have a question about how our energy supply might look in the future? Or do you want to know, for example, how a wave power plant works and how it can efficiently generate electricity? Then send us your question by email. Science journalist Jan Oliver Löfken will investigate the answers and publish them each week in this blog.

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Energy journalist Jan Oliver Löfken writes among other things, for the Technologie Review, Wissenschaft aktuell, Tagesspiegel, Berliner Zeitung and P.M. Magazin on issues involving energy research and industry. For DLR, he answered the Energy question of the week during the Year of Energy 2010.
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